Collapsible tire building form



Nov. 12, 1935. H. c. BOSTWICK COLLAPSIBLE TIRE BUILDING FORM 2 Sheets-Sheet 1 Filed March 11, 1932 Nov. 12, 1935.- H c, BO TWICK 1 2,020,497

COLLAPSIBLE TIRE BUILDING FORM Filed March 11, 1932 2 Sheets-Sheet 2 1 IIIIII'IIIIIIIIII I,

Patented Nov. 12, 1935 PATENT orrlcs COLLAPSIBLE TIRE BUILDING FORM Henry C. Bostwick, Akron,

Akron Standard Mold Company, Akron,

acorporation of Ohio Ohio, assignor to The Ohio,

Application March 11, 1932, Serial No. 598,195 Claims. (01. 1549) This invention relates to collapsible forms or mandrels, and especially those employed in building pneumatic tire casings by the semi-fiat band system. When the ultimate tire casing is of relatively-small bead diameter and large section, difficulties are encountered in collapsing the drum to a sufficiently small compass to enable the formed band to be withdrawn therefrom. The Y principal object of my invention is to provide for an increased amount of collapse of the drum or form without sacrifice of strength or liability to derangement in the operation of the drum.

. Of the accompanying drawings, Fig. 1 is a front 7 elevation, partly'in section, of a drum embody ing my improvements and shown in expanded condition.

Fig. 2 isa front elevation showing the drum collapsed.

Fig. 3 is a longitudinal section on the line 3-3 of Fig. 1, partly in elevation.

Fig. 4 is a. detail section on 1, on an enlarged scale.

Fig. 5 is a section of one of the drum segments looking from the position 5-5 of Fig. 3.

The invention is shown applied to a rotary tirebuilding drum of the general type illustratedin my prior application, Ser. No. 436,716, filed May 18, 1930, but may be used in other connections. These drums are expansible by the action of centrifugal force and collapsible during the rotation thereof by the application of a controlling device such as a brake.

In the drawings, I0 is the rotary shaft of a tire-building machine'and designates the collapsible form or drum as a whole. I2 is a spider or drum-segmentsupport fixed on the end of shaft l0. l3, l3 are a pair of drum segments provided with hinge lugs M at their heel ends pivoted on pins l5 located at opposite ends of the spider l2 and at fixed distances from the central axis of the shaft. |6, |6 are-a complemental pair of drum segments pivoted to swing oppositely to the segments I3 and provided with heel-end hinge lugs straddling the lugs l4 and pivoted to the latter by pins l8 which are spaced angularly in a circumferential direction and radially outward from the pins l5, the combined structure constituting a compound hinge arrangement including centers which are respectively fixed andmovable or floating in relation to the axis of shaft I0.

The free 'or toe ends of the segments l3, when the drum is expanded, overlap those of the segments l6 in a pair of bevelled joints l9. The work-supporting portions of the heel ends of the the line 4-4 of Fig.

segments l3 and I6, under like conditions, meet in a pair of radial joints 20 which are located substantially on the same diameter of the spider |2 as the floating pivots I8 and hence angularly offset in the direction of said pivots from the di- 5 ameter D-D of said spider passing through the radially-fixed pivots l5 of the segments l3. The

.four segments collectively constitute the entire periphery or working surface of the drum, and each of them may be made in parts which are 10 axially adjustable on each other to vary the length of the drum for different widths-of tire bands, as in my aforesaid application.

2| is a rotary control collar or toggle member concentrically surrounding the shaft l0 immel5 diately in the rear of the spider l2 and adapted to turn with respect to the latter. 22 is a tubular control shaft surrounding the drum shaft Ill and composed of two members held in non-turning relation to each other and telescoping one on 20 the other for the purpose of accommodating drums of different axial lengths, the forward member of said shaft being attached to the col- ,lar 2| and its rear end provided with the drum of a manually-operated brake device 23.

The collar 2| is formed with oppositely-extending arms whose outer ends are connected by short toggle links 24 with the underlapping segments l6 near the free ends of the latter. 25 are longer links of angular form connecting points on the collar 2| nearer to the rotary axis thereof With intermediate points on the overlapping segments 3. Spring-projected latch plungers are mounted to slide in guide bushings 26 in the spider |2 parallel with the latters axis of rotation and provided with conical ends to engage complemental sockets in the collar 2| for assisting in the final expanding movement of the seg-; ments as described in my Patent No. 1,866,390, dated July 5, 1932. The symmetrical disposition 40 of the segments and operating connections places the drum substantially in rotational balance when collapsed. The relation of the pivot centers l5 and I8 and the relation of the links 24, 25 and their pivots to the connected parts is such that during collapse the free ends of the underlapping segments f6 first move inwardly in properly timed relation to the overlapping segments l3 to avoid interference. 1

A desirable feature contributing .al reduction in dimensions of the drum in its collapsed condition, along its minor or vertical axis as viewed in Fig. 2, resides in providing arcuate skirt members 21 in radial planes on the two I edges'of each of the segments l3 and I6, each 55 to an addition- I skirt member being mounted on the inner side of one of the edge flanges 28 on the corresponding segment and having a plurality-three in this instance-of radial and semi-radial guide slots occupied by guide pins 30 in the form of skirtretaining cap screws-fixed in the flange 28, leaf springs 3| fixed to the inner side of the segment being interposed between said segment and the outer edge of the skirt member for yieldingly forcing said member inwardly. The drum flanges 28 act as beadseats and may be of different shapes and radial depths according to the bead posture and the height of drum crown desired. Their inner edges are beveled to meet the skirt plates 21, which may normally act as lat-" eral supports and trimming surfaces for the margins of the fabric plies in the tire band.

When the'ou'tlying segments l3 are brought against the underlying segments IS in the collapsed condition, their skirt members 21 yield against the springs 3| to permit the maximum degree of reduction in drum diameter along the minor axis. There may be a similar yielding of skirt members on the underlying segments l6 upon encountering some part of the central structure such as the tubular shaft 22 where a particularly high-crowned drum of small diameter is employed. The yielding of the skirt members-21 on the outlying segments I3 is represented in Fig. 2 as though their movement were in parallelism with themselves although the pressure is at the free end of the segment, but the movement may also be more or less or wholly pivotal on the pin 30 nearest the heel of the segment as a fulcrum, the slots 29 being suitably shaped or sized to permit such pivotal movement.

Rubber bumpers 22' mounted on fixed seats on the spider l2 may be provided as cushioning stops for the arms of the control collar 2| at the limit of the latters drum-collapsing movement.

,In the operation of this invention, drum rotationis counter-clockwise as viewed in Figs. 1 and 2 although the parts might be rearranged for the opposite direction. When it is desired to collapse the drum to remove the tire band which has been built thereon, the driving power is cut off from shaft l0, and while the drum is still in rotation the brake 23 is applied to retard the toggle collar 2! with relation to the drum segments. This causes the free ends of the underlapping segments l6 to be swung inwardly and those of the overlapping segments l3 first to be moved slightly outward,

followed immediately by an inward swinging movement of the segments 13 so that the two segments [3 and IS on each side will lie one over the other in the collapsed condition of the drum, as seen in Fig. 2.

The heel corners of the segments l3, being angularly offset from the diameter DD as previously described, are carried on a rather steep angle inwardly from the expanded circle H of the drum, and the segments l6, having their heels hinged to those of the segments I3, will undergo a corresponding inward movement of their heel corners, so that in the-final collapsed condition of the drum this major diameter, lengthwise of the spider l2, will be reduced very considerably from the expanded diameter of the drum. This aids materially in the removal of a tire band having beads of relatively small diameter. Furthermore, when the skirt members 21 on the segments encounter an underlying structure, said skirt members may yield against the pressure of the springs 3| and thus accomplish a further reduction of dimensionof the collapsed drum along its force when the shaft minor diameter. When the drum I6 is to be used for building another band, it may be automatically expanded by the action of centrifugal I0 is set in rotation.

It will be understood that the described form of embodiment may be considerably varied without departing from the scope of the invention asdefined in the claims.

I claim:

1. A collapsible drum structure comprising a 10 central rotary support, a drum whose periphery is composed entirely of segments movable inwardly' to a collapsed position substantially in rotational balance and including a segment having a heel portion pivoted at a fixed center on the sup- 15 port, and another segment having an adjacent heel portion mounted on a pivot movable inwardly toward the drum center during collapse of the drum, and means rotatable with relation to said support, concentrically with the latters axis of 20 rotation, for collapsing the drum and for so moving said movable pivot during collapse.

2. A collapsible drum structure comprising a rotary spider, and two oppositely-swinging pairs of segments supported by said spider at opposite 25 sides of the latters axis of rotation, a member of each pair being connected with a member of the other pair and with the spider by a compoundhinge device to turn about different centers of which one is fixed on the spider and the other 80 movable around the fixed center.

3. A collapsible drum structure comprising a rotary segment support, a segment having a heel lug pivoted on a center radially fixed on said support, and another segment having a heel lug pivoted on the lug of the first segment on a center spaced from the latters pivot.

4. A collapsible drum structure comprising a rotary shaft having a spider fixed thereon, a pair of segments pivoted at opposite fixed centers 40 thereon, a second pair of segments coacting with the first-said pair to form the drum surface and underlying the members of said first pair when the drum is collapsed, the members of the second pair having floating pivots on the members of the 45 first pair, and a controlling member surrounding said shaft and connected to the respective segments for collapsing the drum during rotation.

panded, in a heel joint offset in the direction of the fioatingpivot, from a diameter of said sup- 55 port passing through the pivotal axis of the first segment.

6. A drum formed of oppositely swinging segments having heel portions connected by a fioating pivot whereby they are hinged one upon another for collapsing the drum, by swinging movement of the segments, to a major diameter smaller than the expanded diameter of the drum, and additional means carried by said segments for reducing the minor diameter of the drum in its 05 collapsed condition.

7. A collapsible chuck comprising a supporting member, an arm secured thereto intermediate its ends, a pair of arcuate segments, each segment pivotally connected to an end of the arm, an arcuate segment pivotally connected to each of the first mentioned segments, and means for moving the free ends of all the segments.

8. A collapsible chuck comprising a supporting member, an arm secured thereto intermediate its [5 segment pivotally connected to an end ends, a pair of arcuate segments, each segment pivotally connected to an end of the arm, an arcuate segment pivotally connected to each of the first mentioned segments adjacent the secured ends of the latter, a shorter arm rotatably mounted intermediate its ends on the supporting member, and means pivotally connecting the free ends of the shorter arm to points adjacent the free ends of one of the arcuate segments.

9. A collapsible chuck comprising a supporting member, an arm secured thereto intermediate its ends, a pair of arcuate segments, each of the arm, an arcuate segment pivotally connected to each of the first mentioned segments, the segments when placed together in end to end relation being adapted to form a substantially circular drum, and means for moving the free ends of all of the segments out of and into end to end relation.

10. A collapsible chuck comprising a supporting member, an arm secured thereto intermediate its ends, pairs of arcuate segments pivotally secured together, one segment of eachpairbeing. pivotally connected to an end of the arm, the segments being so disposed as to form a substantially circular drum, a shorter arm rotatably mounted intermediate its ends on the supporting member, and means pivotally connecting each end of the shorter arm to a point adjacent the free ends of one of the segments.

11. The combination in an annular collapsible tire building form of opposite pairs of adjacent sections, the sections of each pair being pivotally connected by a floating pivot, supporting means at the center of the form formounting the same including a power driven shaft, and means associated with said supporting means and connected with the sections to swing and bodily mdve all of said sections as a whole inwardly from their normal positions in the form circle to collapsed positions in which the sections of each pair embrace a section of each other pair,

said pivots moving inwardly toward the center of the form.

12. The combination in an annular collapsible tire building form of opposite pairs of adjacent sections, the sections of each pair being pivotally connected by a floating pivot, supporting means at the center of the form for mounting the same including relatively rotatable members, and means associated with said supporting means and connected with said members and operable by relative rotation thereof to swing and bodily move all of said sections as a whole inwardly from their normal positions in the form circle to collapsed positions in which the sections of each pair embrace a section of each other pair, said pivots moving inwardly toward the center of the form.

13. The combination in an annular collapsible tire building form of opposite pairs of adjacent 5 sections, the sections of each pair being pivotally connected by a floating pivot, supporting means at the center of the form for mounting the same including a power driven shaft, and means associated with said supporting means and connected with the sections to swing and bodily move all of said sections as a whole inwardly from their normal positions in the form circle, said pivots moving inwardly toward the center of the form.

14. The combination in an annular collapsible tire building form of opposite pairs of adjacent sections, the sections of each pair being pivotally connected by a floating pivot, supporting means at the center of the form for mounting the same including relatively rotatable members, and means associated with said supporting means and connected with said members and operable by relative rotation thereof to swing and bodily move all of said sections asa whole inwardly from their normal positions in the form circle, said pivots moving inwardly toward the center of the form.

15. A drum according to claim 6 in which the additional means is a marginal flange or skirt structure movable on the segment structure.

16. A drum having a hinged segment, means hingedly supporting the same; and a marginal flange or skirt member movable on said segment to reduce the radial depth of the segment.

17. A drum composed of hinged segments 001- lapsible to an overlapping relation, a support by i which theyare hingedly carried, and skirt members guided for relative outward movement on certain of said segments.

18. A drum composed of hinged segments 001- lapsible to an overlapping relation, a carrier therefor, and skirt members on the outlying segments adapted to contact with the underlapping ones and guided for relative outward movement on said outlying segments.

19. In a rotary form, a movable segment having an inner peripheral flange, a skirt member mounted for movement transversely of the outer periphery of said segment on the interior side of said flange and having pin-and-slot guiding connections with the flange, andspring means for inwardly moving said member.

20. A drum having a segment having a hingedly supported heel portion, a support therefor, and an edge skirt pivoted on said segment in the vicinity of the latters heel portion.

HENRY C. BOSTWICK. 

